Geng said it was irresponsible for the Philippines to “politicise the incident without verification”.

Competing claims over the South China Sea are a point of regional contention because trillions of dollars of goods pass through it, and rich petroleum reserves are thought to sit deep beneath its waters.

Reed Bank, an area claimed by Manila and Beijing, is within the Philippines’ 200-nautical-mile exclusive economic zone and far from China’s nearest major landmass.

Manila won a key 2016 ruling against China’s claims in the waterway, but Duterte opted to set it aside in exchange for Chinese investments.

Opposition politicians as well as segments of the public and media charge that Duterte has bartered away Philippine sovereignty with little to show in return.

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